No evidence for parachutes is rarely a clever response

Every now and again I have a twitter day. This means that when I’m out or doing something mundane I will scroll through my twitter feeds responding to multiple tweets and then responding to the replies. Until I develop the self-control of only responding to a few posts I will not be able to do this regularly otherwise I wouldn’t be doing anything else with my life. This Twitter day produced a back and forth with a professor from Canada which resulted in raising the point about lack of evidence for parachutes.

I have heard this before by clinicians who simply do not want to provide evidence for their theories. This has come from an article published in the British Medical Journal in 2003 concluding that:

The problem here is that the conclusion is blending the scientific methods of physics and medicine without acknowledging the difference and then presenting them equally for their own convenience. There is a difference between formulating mathematical models and testing them, and proving theorems with statistical findings. The effect of the parachute is a physics issue, and the effect of the trauma is a medical issue. If medicine develops mathematical medical laws that are so accurate they can make predictions (see physics envy) then you will not have to rely on RCTs. We measure the drag coefficients of parachutes and the laws of physics to engineer a reduction of impact for a range of objects. We then apply the mechanism of the parachute to reduce impact on objects we know is needed. This article’s logic would conclude that we know that infusing insulin in DKA will improve the outcome. However, we haven’t done trials comparing the use of a syringe driver with simply leaving the syringe by the side of the bed with no driving mechanism, so we’ve got you there. In fact, the statistical approach of academic medicine has found that administering insulin is beneficial in DKA. The bioengineers then used the laws of physics to engineer the driver that delivers the insulin. Yale physics professor Ramamurti Shankar introduces his fundamentals of physics course with the point that physics is different from many other sciences. When a man jumps off a cliff physics doesn’t try and work out why he jumped off the cliff, it calculates his velocity and direction. Blending these approaches into one it is either a result of dishonesty or lack of understanding of the scientific method.